It means that the tired bird wants to return to its nest. By this time, it was getting late. The afterglow of the setting sun shines on the back and wings of the flying bird, as if it is carrying the setting sun back to the nest. The word "carry", on the one hand, further exaggerates the scenery and wonderful imagination, and on the other hand, it also highlights the degree of the bird's tiredness, because Carrying a burden is a kind of load, and it is the sun that carries it.
The returning bird is tired, this is the poet's imagination, and it is also the poet's emotion. Bird fatigue is actually also human fatigue. The word "pack" is a further exaggeration of the scenery and a wonderful imagination. On the other hand, it also highlights the degree of the bird's fatigue, because "pack" is a kind of load, and what is carried is the sun. What you see in this way is not just a scenery, but also the poet's experience of life.
Extended information:
The overall framework of this poem adopts the popular short verse style at that time. Small descriptions, concise outlines, prose sentence patterns, and impromptu expressions all show the style of Tagore and Japanese haiku. Liu Dabai focuses on the integration of emotion and scenery in the process of describing nature. This is the so-called combination of poetry and painting and the blending of scenes in old poetry.
The whole poem is rich in the sentiment of old poetry. With just a few strokes, it outlines a beautiful picture of movement in silence and full of sound and color. At the same time, it has the poet's own style, just like the last line. In these two sentences, the reed is personified through "makeup" and "beautiful face", adding some interest and vitality to the whole poem.